Long Island martial-arts magnate Daniel “Tiger” Schulmann threatened to flatten a former black belt student of his after the man complained about a franchise deal, a new federal lawsuit claims.

Joseph Belluomo, 39, of Lindenhurst, claims that Schulmann — who runs 49 karate schools across five states — stiffed him out of profits and eventually yanked his partial ownership of a Seaford location.

According to his federal suit filed in Central Islip, Belluomo said that he first served as a manager at Schulmann’s Massapequa location in 1994 after earning his black belt under the entrepreneurial sensei.

Belluomo said that he eventually came to gain a 50-percent stake in the school, but Schulmann barred him from accessing official financial reports, according to court papers.

He claims that he was also bilked out of “generation checks” given to teachers who produce students who open up new franchise locations of their own.

The karate master’s business model gives 10 percent of profits generated by new franchises to the original instructor, the suit states.

But when Belluomo complained about not receiving his rightful cut last month, Schulmann, 52, “verbally and physically threatened” him, court papers state.

Belluomo claims he was called later that same day by one of his students who said the locks had been changed at the Seaford location.

But Schulmann claims Belluomo was rightfully booted out of his franchise.

“Mr. Belluomo was properly and lawfully terminated for repeated violations of company policy, financial improprieties involving the company’s bank account, and other matters that will come to light in the litigation,” said his attorney, Scott Levenson.

Belluomo did not return a call for comment.

His lawyer, Saul Zabell, said, “To us, it is absolutely offensive that Tiger would prey on young businessmen who start off with his karate organization at a young age. He coerces them into making financial investments that he has no intention of honoring.”

Schulmann was fined $195,000 by the New York state attorney general in 2000 for deceptive business practices at his karate schools.